A network architecture with Policy and Charging Control (PCC) functions includes a Policy and Charging Rules Function (PCRF), a Policy and Charging Enforcement Function (PCEF), and an Application Function (AF), as shown in FIG. 1. The PCRF is adapted to dynamically generate a Quality of Service (QoS) and charging rule (“PCC rule”) for a user service stream according to an operation policy and service application information. The PCEF is a gateway that executes the PCC rule. The AF is generally a service control server. A user terminal needs to access the AF to initiate a service connection. The AF provides terminal service information for the PCRF. The PCRF communicates with the PCEF/AF through a Diameter protocol. The PCEF/AF is a client, and the PCRF is a server.
Multiple PCRFs may be deployed in a PCC network. When a user terminal is connected to a data network, one of the PCRFs may be selected. After a PCRF is selected, the selected PCRF serves as the PCC server of the data connection till the data connection to the data network is disconnected. Multiple clients in a network need to access the PCRF for the same data connection. Therefore, a PCRF management entity is introduced into the PCC network to manage the mapping relation between the data connection and the PCRF that serves the data connection, where the data connection exists between the user and the data network. If any the policy control request message sent by the clients does not carry destination PCRF information, the policy control request message needs to pass through the PCRF management entity. The PCRF management entity acquires the destination PCRF information according to the prestored mapping relation between the data connection and the PCRF that serves the data connection, and sends the policy control request message to the destination PCRF, thus ensuring that different clients use the same PCRF as the PCC server when the different clients request for allocating a server for the same data connection.
When a client sets up a connection with the PCC server for the first time, the PCRF management entity needs to select an available PCC server and return information about the selected PCC server to the client, and record the mapping relation between the data connection and the PCC server. The client sends a policy control request message to the available PCC server, instructing the PCC server to set up a data connection. In fact, the route between the client and the allocated PCC server may be blocked, which leads to failure of setting up the data connection between the client and the allocated PCC server. When the client selects a PCC server again, the setup of the policy control session corresponding to the data connection still fails. This is because the PCRF management entity retains the mapping relation between the data connection and the PCC server that is selected previously and thus the returned information about a PCC server is still the information about the PCC server that is selected last time.
After the data connection between the client and the PCC server is set up successfully, one party can acquire the host name of the other party. Thus, the information exchanged subsequently can be routed to the peer party through host name. For example, the policy control request message subsequently sent by the client to the PCC server carries the destination PCRF information, and thus it is not necessary to query the PCRF management entity for the destination PCRF information. Therefore, when the data connection is released, the policy control request message that indicates releasing the data connection carries the destination PCRF information. This causes that the policy control request message does not pass through the PCRF management entity. After the data connection from the user to the data network is released, the PCRF management entity still retains the mapping relation between the data connection and the PCRF that serves the data connection. When the user accesses the data network again, the policy control request message that indicates setting up a data connection is sent to the PCRF management entity. The PCRF management entity returns the previously stored PCRF information corresponding to the data connection. The client uses the PCRF as a destination PCRF, and sends the policy control request message that indicates setting up a data connection. However, when the PCRF fails, it is impossible to set up the policy control session corresponding to the data connection.
After the client is connected to the PCC server for the first time, the PCRF management entity stores the mapping relation between the data connection and the PCC server that serves the data connection. During user handover, a new client needs to set up a policy control session with the previous PCC server. The prior art does not mention how a PCRF management entity handles the mapping relation between the prestored data connection and the PCC server that serves the data connection in the case that the setup of the policy control session between the new client and the PCC server fails.